The Jewel of Eae-Nirin

The Jewel of Eae-Nirin, currently housed in the main hall of the Museum of Mindbending Ultimate Artifacts (formerly the Museum of Quainteries and Oddities) on the campus of the Adventurer's University of Caldonia, is an item of much speculation, rumor, and tale spinning. There are those, of course, who claim that none of the stories about the jewel in question are remotely true and, in fact, there is no actual Jewel of Eae-Nirin at all. This argument was revised (upon pointing out that there is a jewel on display in the museum, and that jewel is referred to as the Jewel of Eae-Nirin) to state that there is no jewel that actually matches to any of the stories told about the Jewel of Eae-Nirin. Then a believer told a tale about going to visit the museum with her great-aunt Tildy and that the jewel was quite impressive, and shiny. This story being true, the skeptics were again put to silence.
The Jewel of Eae-Nirin is at the center of the legends of empires rising and falling, conquerors conquering, tyrants... tyranting. In these stories, the Jewel variously has the power to banish demons (real ones, not Jahannon), summoning angels (real ones, not Sera-im banishing jahannon, summoning sera-im, laying waste to armies, restoring crops, causing floods, creating droughts, making the object of your affection fall in love with you, and even, according to a favorite tale told at the Restful Home for Aged and Useless Explorers, the power to instantly cure both bunions and incontinence.
It should be noted that the museum does not allow any of these powers to be tested, especially not by the School of Comparative Abominations. We're looking at you, Chet Bumble-Fitz.